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%I #46 Mar 19 2017 19:36:11
%S 0,455,13072,111111,536312,1864135,5227320,12597767,27126736,53543367,
%T 98611520,171644935,285080712,455111111,702373672,1052699655,
%U 1537920800,2196734407,3075626736,4229854727,5724486040,7635497415,10050931352,13072111111,16814914032,21411103175,27009717280
%N a(n) = ((3*n + 1)^6 - 1)/9.
%C If n is in the sequence, then so is n followed by q ones, where q is congruent to 0 mod 6. For example, 13072 is a term, so 13072111111 is also.
%e a(2) =81*2^6 + 162*2^5 + 135*2^4 + 60*2^3 + 15*2^2 + 2*2 = 13072.
%p f:=n->((3*n+1)^6-1)/9; [seq(f(n),n=0..30)];
%K nonn,easy
%O 0,2
%A _Jake Lawrence_, Mar 05 2017
%E Edited by _N. J. A. Sloane_, Mar 07 2017